The present invention relates to a method of producing a biodegradable product which is intended, for instance, for only temporarily containing foodstuffs, or of producing objects such as a container for snacks, a beaker for hot or cold drink, etc., which product is manufactured under pressure and heat in a mould, based on a basic material whose composition comprises amylose-comprising flour derived from an edible crop plant, wood flour, natural wax and water.
Methods of the above-mentioned kind are known from the prior art, for instance, from the published Dutch patent applications Nos. 9402248 and 9100590. The object of these kinds of methods is to provide disposable products which are to be used only for a short period of time such as small containers, bowls, plates, etc. of a kind whose production and waste disposal cause the least possible environmental pollution.
Up to date it has been proven to be impossible to manufacture a product in accordance with the methods of the prior art which is suitable to contain for a reasonable length of time a wet and at the same time hot substance, such as a meal, soup, etc. heated in the microwave oven. For such applications the product, for instance a container for a meal, is required to be resistant to the heat from the substance it contains, and likewise, it must not readily loose its strength and firmness as a result of the moisture it contains.
Another disadvantage of the products according to the prior art is that they are relatively breakable. Further, their manufacture involves a relatively complicated process in which the components of the basic material are mixed to a relatively thin kind of batter, the batter is conveyed via a pipe system to the mould cavity where, with the aid of an injection nozzle, it is injected into the mould. A further disadvantage is that this manner of working results in a relatively great burden on the environment. In view of the fact that the batter is very perishables the mixing device, the mixing vessel and the pipe system must be cleaned regularly with water. The polluted water is then discharged into the sewer system which, in consideration of the environment, is undesirable.
The object of the invention is to provide a method of the kind mentioned in the preamble in which these disadvantages are substantially met, and by which also new advantages are provided, and is characterized in that the composition of the basic material consists substantially of a moist granulate substantially comprising the following four ingredients: 50-250 parts by weight of flour, 10-85 parts by weight wood flour, 2-30 parts by weight natural wax and 50-250 parts by weight water, the four ingredients together making up substantially 100% of the basic material.
One embodiment includes the four ingredients in the amounts of 75-200 parts by weight flour, 20-25 parts by weight wood flour, 4-20 parts by weight natural wax and 75-200 parts by weight water. In another embodiment, the four ingredients are included in the amounts of 100-175 parts by weight flour, 30-60 parts by weight wood flour, 5-18 parts by weight natural wax and 100-155 parts by weight water. A preferred embodiment includes the four ingredients in the amounts of 140-150 parts by weight flour, 40-50 parts by weight wood flour, 8-10 parts by weight natural wax and 140-150 parts by weight water.